ARDMS SPI EXAM STUDY GUIDE 180 Questions with Verified Answers,100% CORRECT

ARDMS SPI EXAM STUDY GUIDE 180 Questions with Verified Answers In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS) will... - CORRECT ANSWER Remain the Same because stiffness and density affect Propagation Speed. What is the audible range? - CORRECT ANSWER 20-20,000Hz >20,000Hz=Ultrasound Frequency is measured in - CORRECT ANSWER Hertz (Hz) is Cycles per Second Not affected by sonographer Increase Frequency; Decrease Depth A period is the length of time it takes for - CORRECT ANSWER one complete wavelength to pass a fixed point PRP is determined by - CORRECT ANSWER Transmit time and receive time. Period is measured in - CORRECT ANSWER Time (μs) When the sonographer changes the imaging depth what parameters are changed? - CORRECT ANSWER PRP, PRF, Duty Factor What is duty factor? - CORRECT ANSWER The percentage or fraction of time that the system is transmitting a pulse (Time Sound is ON or ON-Time). Propagation Speed in SOFT TISSUE - CORRECT ANSWER 1.54 mm/μs (1540 m/sec) Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period - CORRECT ANSWER Time, (μs) Pulse duration is determined by - CORRECT ANSWER Sound Source Only Pulse Duration is controlled by - CORRECT ANSWER the ultrasound system and transducer Pulse Duration Formula - CORRECT ANSWER pulse duration (μs) = # cycles in pulse/frequency(MHz) PD= Number of cycles in Pulse/ Frequency(Hz) Spatial Pulse Length (SPL) (measurement) - CORRECT ANSWER The distance that a pulse occupies in space from the start to the end of a pulse. (mm) Typical values for spatial pulse length in soft tissue. - CORRECT ANSWER 0.1 to 1.0 mm Spatial pulse length is determined by - CORRECT ANSWER sound source and medium Spatial Pulse Length is directly proportional to - CORRECT ANSWER the Number of Cycles in the Pulse and the Wavelength (Directly Proportional means that increased SPL will increase both the number of cycles in the pulse and the wavelength if increased). Spatial pulse length is inversely proportional to - CORRECT ANSWER Frequency (MHz) (Inversely Proportional means that increased SPL will lower frequency. This is because axial resolution is better with lower frequency) Pulse Duration (PD) - CORRECT ANSWER The actual time from the start of a pulse to the end of that pulse; a single transmit, talking, or "on" time. Time the pulse is on typically measured in (ms). Pulse Length - CORRECT ANSWER The distance of the pulse start to end or the duration or length of a single pulse Pulse Length is typically measured in (mm). the ability of an object to resist compression and relates to the hardness of a medium? - CORRECT ANSWER Stiffness. Think: ↑ Stiffness ↑ Speed ↓ Density ↑ Speed An increase in pulse repetition frequency would lead to: - CORRECT ANSWER Increasing pulse repetition frequency, increases duty factor. ↑ PRF ↑ Duty Factor Which of the following would have the highest propagation speed? - CORRECT ANSWER Bone has the highest propagation speed, at m/s. What has the lowest propagation speed? - CORRECT ANSWER air technically has the lowest propagation speed at 300 m/s Which has the Slowest Propagation Speed? Water Soft Tissue Bone Lung tissue - CORRECT ANSWER Lung Tissue As imaging depth increases, the pulse repetition frequency (PRF) must: - CORRECT ANSWER Decrease As imaging depth increase, pulse repeition freqency (PRF) decreases. ↑ Imaging Depth ↓ PRF What describes the amount of refraction that occurs at an interface? - CORRECT ANSWER Snell's law Refraction: the redirection of the transmitted sound beam Snell's law describes the angle of transmission at an interface based on the angle of incidence and the propagation speeds of the two media. Pressure is typically expressed in: - CORRECT ANSWER Pascals (Pa) The typical range of frequency for diagnostic ultrasound imaging is - CORRECT ANSWER 1-20 Mhz is the typical range of frequency for diagnostic ultrasound imaging. The attentuation coefficient in soft tissue is equal to: - CORRECT ANSWER Attentuation Coeffcient = 1/2 (one half of the frequency in soft tissue) The attentuation coeffcient (in dB/cm) is the rate at which sound is attentuated per unit depth. Micro is denoted as: - CORRECT ANSWER Micro is denoted as millionth (µ) What is described as the distance over which one cycle occurs? - CORRECT ANSWER Wavelength is distance over which one cycle occurs, or the distance from the beginning of one cycle to the end of the same cycle. Remember, it asks for distance over which one cycle occurs. Stiffness and propagation speed are - CORRECT ANSWER Directly Related Also remember: ↑ Stiffness ↑ Speed ↓ Density ↑ Speed Areas of high pressure and density are referred to as: - CORRECT ANSWER Compressions What type of wave is sound? - CORRECT ANSWER Mechanical and Longitudinal Wave The frequency ranges for ultrasound are: - CORRECT ANSWER Ultrasound frequency is 20 to 20,000 Hz The speed of sound in soft tissue is - CORRECT ANSWER Speed of sound in soft tissue is 1540 m/s Which transducer fires the elements in groups? - CORRECT ANSWER Linear sequenced array fires the elements in groups The units for wavelength is - CORRECT ANSWER Wavelength units are (Millimeters) Enhancement is caused by - CORRECT ANSWER Weakly attenuating structures The wavelength in a material having a propagation speed of 1.5 mm/µs employing a transudcer frequency of 5.0 MHz is: - CORRECT ANSWER 0.3 mm wavelength = c/f 1.5 mm/µs / 5 MHz = 0.3 mm An ultrasound transducer converts - CORRECT ANSWER Electrical energy into Mechanical energy and vice versa Lowest attenuation to highest - CORRECT ANSWER bone, muscle, fat, air If frequency doubles, what happens to the wavelength? - CORRECT ANSWER Wavelength is decreased by 1/2 Frequency and Wavelength are: - CORRECT ANSWER Inversely related What happens to intensity if the amplitude of a signal is halved? - CORRECT ANSWER Amplitude halved will result in intensity quartered amplitude = intensity2 Ultrasound pulses contain a range of frequencies called - CORRECT ANSWER bandwidth How is time related to frequency - CORRECT ANSWER inversely What describes the percentage of time that sound is on? - CORRECT ANSWER Duty factor is the percentage of time the sound is being transmitted A 3 dB gain would indicate an increase in intensity by: - CORRECT ANSWER Two Times 3 dB results in doubling of intensity (or power) The intensity of the ultraosund beam is usually greater at the focal zone because of - CORRECT ANSWER the smaller beam diameter Attenuation denotes - CORRECT ANSWER Progressive weakening of the sound beam as it travels Which of the following has the lowest intensity - CORRECT ANSWER SATA is the lowest of the intensities What is the definition of the beam uniformity ratio? - CORRECT ANSWER Beam Uniformity Ratio = Spatial peak / Spatial average Continuous wave Doppler has a duty factor of - CORRECT ANSWER 100% CW Doppler is always transmitting sound making it's duty factor 100% The spatial pulse length is defined as: - CORRECT ANSWER the product of the wavelength and the number of cycles in a pulse? SPL = wavelength x cycles What term and philosophy relates the amount of exposure time for the sonographer and patient during a diagnostic ultrasound examination? - CORRECT ANSWER ALARA - As Low As Reasonably Achievable What term is defined as the body's pathologic response to illness, trauma or severe physiologic or emotional stress? - CORRECT ANSWER Shock The inertia of the medium describes its: - CORRECT ANSWER Density. Inertia is described by Newton's principle - an object at rest will stay at rest. An object in motion stays in motion, unless acted on by an outside force. Greatest attenuation would occur at: - CORRECT ANSWER long distance with high frequency A 3MHz sound beam travels through two media. It attenuates 5 dB in medium A and 6 dB in medium B. - CORRECT ANSWER Total attentuation is 11 dB Attenuation simply adds up as sound travels. What would you do to create a wave with the highest possible intensity? - CORRECT ANSWER Highest intensity would occur with a short distance and low frequency. Lowest Attenuation is found at - CORRECT ANSWER lowest frequency, with the shortest path length. What results in the most attenuation? - CORRECT ANSWER most attenuation occurs at the high frequency and long distance. Which media has the greatest attenuation and the slowest speed? - CORRECT ANSWER Air Air > Bone & Lung > Soft Tissue > Water What type of wave is sound? - CORRECT ANSWER Mechanical and Longitudinal wave The speed of sound in soft tissue: - CORRECT ANSWER 1540 m/s The unit for wavelength: - CORRECT ANSWER Distance (mm) Enhancement is caused by: - CORRECT ANSWER weakly attenuating structures Lowest attenuating to highest attenuation - CORRECT ANSWER Fat-Muscle-Bone-Air List propagation speed from lowest to highest - CORRECT ANSWER Air-Fat-Muscle-Bone Which of these media has the lowest attenuation and the greatest speed? bone tendon lung fat air - CORRECT ANSWER Bone Air > Bone & Lung > Soft Tissue > Water Bone is more stiff than air (remember ↑ stiffness, ↑ speed) What describes the physics of refraction mathematically? - CORRECT ANSWER Snell's Law What is a reflection arising from a rough boundary? - CORRECT ANSWER Non-specular Specular reflection is from a smooth reflector (like mirrors). They return in one direction. Whereas, non-specular is diffuse or scatter, reflection from a rough boundary. When time-of-flight is measured, we can determine the ________? - CORRECT ANSWER Reflector Depth A sound pulse travels from the transducer to location A, reflects off of it, and returns to the transducer in 130 μs. How deep is location A? - CORRECT ANSWER Location A is 10 cm from the transducer Total travel distance would be 20 cm Which of the following would be considered the narrowest part of a sound beam? - CORRECT ANSWER The focus is the narrowest part of the beam Which of the following is the part of the transducer that stops the ringing of the element? - CORRECT ANSWER The damping material helps stop the ringing of the transducer Along with image depth, which of the following also determines the frame rate? - CORRECT ANSWER Image depth and the number of lines per frame determines the frame rate. Which type of resolution is an accurate representation of moving structures? - CORRECT ANSWER Temporal resolution, also known as frame rate, is the ability to display moving structures in real time. What type of transducer that utilizes elements arranged in a concentric pattern? - CORRECT ANSWER The annular array transducer ultilizes elements arranged in concentric rings What transducer would be considered an advantage of linear array over a phased array transducer? - CORRECT ANSWER The linear array has a wider near field of view compared to a phased array transducer Mechanical Transducers: - CORRECT ANSWER Have moving parts Uses a motor to steer the beam Most transducers are no longer mechanical May be focused with a lens or phased focuses Along with crystal diameter, the divergence in the far field is also determined by... - CORRECT ANSWER Frequency and crystal diameter determines the divergence in the far field What would cause an increase in frame rate? - CORRECT ANSWER Decreasing the imaging depthwould increase the frame rate When you decrease the imaging depth it can work faster (increase frame rate) because it doesn't have to go as deep. The diameter of the beam in the Fresnel zone/near zone does what? - CORRECT ANSWER Decreases Which resolution is best in the clinical imaging? - CORRECT ANSWER Axial resolution is best in imaging will increase the near zone length? - CORRECT ANSWER A large crystal diameter with high frequency would increase the near zone length What will decrease beam divergence in the far field? - CORRECT ANSWER A large crystal diameter and high frequency would decrease the beam divergence in the far field Imaging transducers have - CORRECT ANSWER Imaging transducers have low quality factors and wide bandwidiths. What is the speed of a wave with a wavelength of 3 m and a frequency of .1 Hz? - CORRECT ANSWER 0.3 m/s wave speed= frequency x wavelength Wavelength and Frequency are - CORRECT ANSWER inversely proportional to each other How do you calculate the speed of a wave given the wavelength and frequency? - CORRECT ANSWER Frequency (Hz) x wavelength (distance)= Wave Speed What is the speed of a wave with a frequency of 2 Hz and a wavelength of 87 m? - CORRECT ANSWER 174 m/s 2Hz x 87m= 174m/s speed of a wave: frequency x wavelength The ____ of a wave is the number of wavelengths that pass a fixed point in a second. - CORRECT ANSWER frequency Frequency is the number of wavelengths that pass a fixed point in a second A sound wave is traveling in the body and propagates from muscle to air. What percentage of the sound wave is most likely reflected at the muscle-air boundary? - CORRECT ANSWER 75% Which of the following lists is in decreasing order? - CORRECT ANSWER Mega, kilo, deca, milli, nano The conversion of sound energy to heat - CORRECT ANSWER Absorption Acoustic Speckle - CORRECT ANSWER the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image Acoustic Variables - CORRECT ANSWER changes that occur within a medium as a result of sound traveling through that medium Amplitude - CORRECT ANSWER The maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector Attenuation - CORRECT ANSWER A decrease in the amplitude and intensity of the sound beam as sound travels through tissue. Attenuation Coefficient - CORRECT ANSWER The rate at which sound is attenuated per unit depth Axial Resolution - CORRECT ANSWER The ability to accurately identify reflectors that are arranged parallel to the ultrasound beam Backscatter - CORRECT ANSWER Scattered sound waves that make their way back to the transducer and produce an image on the display Beam Uniformity Ratio - CORRECT ANSWER The ratio of the center intensity to the average spatial intensity; also referred to as the SP/SA factor or beam uniformity coefficient Capacitive Micromachined Ultrasound Transducers - CORRECT ANSWER Technology used to create comparable transducer technology to piezoelectric materials Compression - CORRECT ANSWER An area in the sound wave of high pressure and density Continuous Wave - CORRECT ANSWER Sound that is continuously transmitted Damping - CORRECT ANSWER The process of reducing the number of cycles of each pulse in order to improve axial resolution Decibels - CORRECT ANSWER A unit that establishes a relationship or comparison between two values of power, intensity, or amplitude Density - CORRECT ANSWER Mass per unit volume Directly Related - CORRECT ANSWER Relationship that implies that if one variable decreases, the other also decreases or if one variable increases, the other also increases; also referred to as Directly Proportional Distance - CORRECT ANSWER How far apart objects are AKA vibration or displacement Duty Factor - CORRECT ANSWER The percentage of time that sound is actually being produced Elasticity - CORRECT ANSWER The ability of a material to bounce back after being disturbed Frequency (Hz) - CORRECT ANSWER The number of cycles per second Half-Intensity Depth - CORRECT ANSWER the depth at which sound has lost half of its intensity Half Intensity Depth is also called - CORRECT ANSWER Half-Value Layer Thickness Hertz (Hz) - CORRECT ANSWER A unit of frequency Hydrophone - CORRECT ANSWER a device used to measure the output intensity of the transducer Impedence - CORRECT ANSWER the resistance to the propagation of sound through a medium. Inertia - CORRECT ANSWER Newton's principle that states that an object at rest stays at rest and an object in motion stays in motion, unless acted on by an outside force. Intensity - CORRECT ANSWER the power of a wave divided by the area over which it is spread; the energy per unit area Intensity Reflection Coefficient (IRC) - CORRECT ANSWER The percentage of sound reflected at an interface. The percentage of the sounds intensity that is reflected when sound hits a boundary or tissue Interface is the dividing line between 2 different media. Intensity Transmission Coefficient (ITC) - CORRECT ANSWER The percentage of sound transmitted at an interface -or- The percentage of intensity that continues forward after beam strikes an interface Interface - CORRECT ANSWER The dividing line between two different media Inversely Related - CORRECT ANSWER Relationship that implies that if one variable decreases, the other increases or if one variable increases, the other decreases; also referred to as inversely proportional Longitudinal Wave - CORRECT ANSWER Waves in which the molecules of the medium vibrate back and forth in the same direction that the waves are traveling. Medium - CORRECT ANSWER Any form of matter; Solid, Liquid, or Gas Non-specular Reflectors - CORRECT ANSWER Reflectors that are smaller than the wavelength of the incident beam Which gain will increase the risk of bioeffects? - CORRECT ANSWER Transmit What is considered the memory of an ultrasound instrument? - CORRECT ANSWER Digital Scan Converter Spectral Broadening Suggests - CORRECT ANSWER Turbulent Flow What happens to axial resolution with Pulse Wave Doppler - CORRECT ANSWER Axial Resolution Degrades when using Pulse Wave Doppler What color is usually used in Color Flow Doppler variance map to indicate turbulent flow? - CORRECT ANSWER Green A Doppler (high pass filter) eliminates? - CORRECT ANSWER high amplitude signals, low velocity flow The Doppler wall filter is considered a: - CORRECT ANSWER High Pass Filter The Nyquist Limit is equal to: - CORRECT ANSWER PRF/2 Pulse Repetition Frequency divided by two Multiple echoes, equally spaced originating from a gas bubble is called - CORRECT ANSWER Ring Down An increase in red blood cell velocity will____________Doppler Shift: - CORRECT ANSWER Increase increase in rbc velocity increases Doppler shift The primary advantage of CW Doppler is: - CORRECT ANSWER Absence of Sampling Rate The range for ultrasound begins: - CORRECT ANSWER at 20,000Hz or 20KHz (Useful Frequency Range for Clinical Imaging is 2MHz-10MHz) Which instrument control affects the amplitude (db) of the outgoing signal? - CORRECT ANSWER Transmit Gain; Amplitude can be affected by the sonographer What is used to convert Doppler shift information into color? - CORRECT ANSWER Autocorrelation What is used to process conventional Doppler shift information but is too slow of a method for Color Doppler? - CORRECT ANSWER Fast Fourier transform Pulse Repetition Frequency - CORRECT ANSWER The number of pulses that an ultrasound system transmits into the body each second. Unit: Hz. Typically 4-15 KHz. PRF and Depth of View are inversely related. When the system is imaging deeper, the pulse repetition frequency is lower, as well as, the number of pulses created each second. What is the best way to increase the near field length of an ultrasound beam? - CORRECT ANSWER Increase Transducer Diameter What is the range of frequencies produced by a dampened PZT element? - CORRECT ANSWER bandwidth What is bandwidth? - CORRECT ANSWER range of frequencies in a pulse The percentage of time that the ultrasound instrument is emitting ultrasound is called? - CORRECT ANSWER Duty Factor The maximum value is 1, the minimum is 0 What is the unit of Duty Factor? - CORRECT ANSWER Duty Factor is Unit-less If the ultrasound is produced as a continuous wave (CW), the duty factor will have a value of 1. With Pulsed Wave the whole value of On-Time is fractioned. What is Q-factor or Quality Factor? - CORRECT ANSWER The "Q factor" describes the bandwidth of the sound emanating from a transducer Transducer Q Factor (Q = Quality) is associated with two characteristics of the crystal • purity of their sound and • length of time the sound persists (Unitless measurement) Fundamental Frequency(Hz)/Bandwidth(range of frequency in the pulse) The unit of duty factor is: - CORRECT ANSWER Unitless Clinical imaging transducers are: - CORRECT ANSWER Wide bandwidth; Low Q factor Wide range of frequencies in the pulse and short period of time that the sound is emitted (pulsed wave) Power/Area= - CORRECT ANSWER Intensity Increasing wavelength will_______frequency? - CORRECT ANSWER Decrease Beam Properties - CORRECT ANSWER The ultrasound beam propagates as a longitudinal wave from the transducer surface into the propagation medium, and exhibits two distinct beam patterns: - a slightly converging beam out to a distance specified by the geometry and frequency of the transducer (the near field), and - a diverging beam beyond that point (the far field). Does Beam Width directly affect frame rate? - CORRECT ANSWER No: The following directly affect frame rate: Depth of Penetration Field of View Number of Focuses and Line Density What affects frame rate? - CORRECT ANSWER Depth of Penetration, Field of View, Number of Focuses, and Line Density. Frame Rate= Number of Frames/Second When will a reflection occur at the boundary of two media? - CORRECT ANSWER If the acoustic impedances of the tow media are different. Snell's Law - CORRECT ANSWER Describes the relationship between the angles and the velocities of the waves. When an ultrasonic wave passes through an interface between two materials at an oblique angle, and the materials have different indices of refraction, both reflected and refracted waves are produced In ultrasound, Snell's Law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, for a given frequency. The Angle of Incidence - CORRECT ANSWER Refers to the angle of deviation from a perpendicular line to the surface of the tissue Therefore, the desired orthogonal(perpendicular) incident wave in ultrasound should be considered to have an angle of incidence of zero. When the angle of incidence is greater, fewer sound waves are reflected back to the transducer resulting in a more hypoechoic (darker) image with less clarity. The optimal reflection with the most sound waves occurs when the angle of incidence approaches zero and is virtually perpendicular (orthogonal) to the tissue of interest. Law of Reflection - CORRECT ANSWER the angle of incidence is equal to the angle of reflection Mechanical Transducers utilize what kind of focusing? - CORRECT ANSWER Fixed Focusing: Sonographers cannot determine the location of # of foci. Mechanical Transducers use Cross-Sectional imaging, rotating wheel, wobbler, and oscillating mirror. The transducer frequency is primarily determined by the transducer element's what? - CORRECT ANSWER Thickness For pulsed transducers..the main or center frequency of the transducer is determined by the thickness and the propagation speed of the piezoelectric material. PZT is also called - CORRECT ANSWER Ceramic, Active Element, or Crystal A strongly focused transducer implies a: - CORRECT ANSWER Short focal length and Increased Beam Divergence B-mode displays reflector: - CORRECT ANSWER Amplitude and Distance An increase in the number of pixels on the display will improve: - CORRECT ANSWER Detail Resolution Propagation speed is determined by - CORRECT ANSWER Medium only - density and stiffness of media Bulk Modulus describes the change in the material's volume under external stress. Increasing transmit gain increases everything except: - CORRECT ANSWER Frequency Gain is a receiving function •Does not impact how much energy is transmitted to patient (i.e. power) The correct depth placement of reflectors depends primarily upon: - CORRECT ANSWER Propagation Speed What will increase the color flow jet area displayed? - CORRECT ANSWER Increasing Color Gain Increasing Propagation Speed - CORRECT ANSWER air: 330 m/sec fat: 1450 m/sec water: 1480 m/sec soft tissue: 1540 m/sec liver: 1550 m/sec kidney: 1560 m/sec blood: 1570 m/sec muscle: 1580 m/sec bone: 4080 m/sec The most common type of transducer used in echo is: - CORRECT ANSWER Sector Phased Array What are the four acoustic variables? - CORRECT ANSWER 1. Temperature 2. Density 3. Particle Motion 4. Pressure The Doppler effect is presented as a ___________________ when the source and the receiver are in motion relative to each other. - CORRECT ANSWER Frequency Shift + or - Doppler Shift - CORRECT ANSWER receiver toward the transducer= + shift receiver away from transducer = - shift + toward (above baseline) - away (below baseline) - CORRECT ANSWER